docs: def __unpack_tgz(self, filename):
          """Unpack the `tar.gz`, `tgz` compressed file format"""
          if isinstance(filename, string_types) and self.__isValidTGZ(filename) and tarfile.is_tarfile(filename):
              with tarfile.open(filename, mode='r:gz') as t:
                  for name in t.getnames():
                      t.extract(name, self.plugin_abspath)
          else:
              raise TarError("Invalid Plugin Compressed File")